1. Field of the Invention
This invention relates to a rotary damper and an opening and closing mechanism for a vehicle door employing the rotary damper.
2. Related Art
Vehicle doors which open and close with respect to a vehicle body, such as tailgates of automobiles, are commonly equipped with a rotary damper in order to enable the vehicle door to open and close smoothly. A rotary damper applies rotational resistance to a member which undergoes rotational movement and attenuates the rotational movement. It typically includes a rotor which is connected to a member which undergoes rotational movement. The rotor rotates while resisting a mechanical frictional force or fluid resistance produced by a fluid such as oil. For example, JP 2007-63884 A (corresponding to US 2009/0139057 A1) discloses a rotary damper which is mounted on the bottom surface of a tailgate of a vehicle and which is connected to a shaft which rotates relative to the tailgate as the tailgate opens and closes.
In the rotary damper disclosed in JP 2007-63884 A, the rotary damper and the rotating shaft are respectively secured to the vehicle body and to the tailgate which rotates with respect to the vehicle body. As a result, when the tailgate is opened and closed, if there is a deviation in the position or attitude of the rotary damper with respect to the rotating shaft, there were the problems that the durability of the rotary damper decreased or the resistance to rotation generated by the damper varied.